This is a single-institution, prospective, randomized study comparing the medial parapatellar and subvastus approaches in primary total knee arthroplasty using continuous, implant-based gait monitoring. Patients receiving a Zimmer Persona IQ smart implant will be followed preoperatively and through the first 30 days post-operatively, with extended follow-up to 6 months. Preoperative activity is captured using iPhone Health step-count data, while post-operative recovery is assessed using continuous tibial implant data, including step count, range of motion, cadence, walking speed, stride length, and distance. These objective metrics are correlated with PROMs. The primary outcome is daily step count. Secondary outcomes include early functional milestones, pain, and patient-reported functional scores. This study is designed to characterize early recovery trajectories and determine whether meaningful differences exist between surgical approaches.
All patients older than 18 years of age who plan to undergo medial congruent polyethylene bearing primary TKA with a PIQ
Eligible for both approaches
Have an iPhone and willing to "wear" it for two weeks preoperatively to get an estimated average stepcount
Provide informed consent
Patients with TKA revisions
Patients with insufficient pre-operative range of motion in the operative knee (flexion contracture of > 20 degrees or < 90° of knee flexion)
Patients with Contralateral TKA within study time frame
Patients with TKA other than medial congruent polyethylene bearing